Uh huh. I fully endorse your analysis. Except that I'd say (1) would still leave us far better off than the typical confrontation-allowed political forum out there, because LWers would probably at least be willing to state their positions clearly, and would accept help in clarifying/refining those positions - even if the art of changing one's mind should be lost, LW discussion would still retain some value. So I'd rather have (1) than (3).

Please consider that both Torture vs Specks and Three Worlds Collide are, as it seems to me, very much political - indeed, the latter could be construed as today's very Blue vs Green with a touch of imagination, yet the debates on those have been quite OK.